docs: add opencode-puter-auth to ecosystem plugins

[chindris-mihai-alexandru]

Summary

Adds opencode-puter-auth to the ecosystem plugins list.

About the Plugin

opencode-puter-auth enables OpenCode to authenticate with Puter.com via OAuth, providing access to 500+ AI models including:

• Claude Opus 4.5, Sonnet 4.5, Haiku 4.5
• GPT-5.2, o3-mini, o4-mini
• Gemini 2.5 Pro/Flash
• DeepSeek R1
• And many more

Features

• Browser-based OAuth authentication
• Real-time SSE streaming
• Tool/function calling support
• Full AI SDK v3 provider implementation

npm

Installation

{
  "plugin": ["opencode-puter-auth"],
  "provider": {
    "puter": {
      "npm": "opencode-puter-auth",
      "models": { ... }
    }
  }
}

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Happy to make any changes if needed!